The present invention generally relates to a method and apparatus for acquiring and recording a sample of an environment and, more particularly, to a method and apparatus that allows the stored recording to be verified as an authentic, unaltered sample of the environment.
One purpose of the present invention is to provide a solution to the problem of either deliberate or inadvertent alteration of recordings. In this context, xe2x80x9crecordingsxe2x80x9d refers to all recordings, including digital images, data files, and the more common audio recording.
Photographs, movies and printed materials have historically been regarded as media that can be trusted to be authentic copies of the original. Early attempts at alteration of photographs for the purposes of revisionist history were almost comically detectable with five people sitting at a table, but six pairs of legs underneath. Hand written, permanently bound, notebooks are used in research laboratories for their resistance against attempts at alteration. Recent technological advances have brought the ability to alter images to the neophyte level. When a master employs the advanced technology the alterations are almost completely undetectable. For this reason digital photography is seldom used in situations when xe2x80x9cchain of custodyxe2x80x9d requirements exist to protect the authenticity of a recording be it photographic, written or auditory. For example, the picture of an accident scene could be altered to show bottles of alcoholic beverages around the driver, even if those bottles hadn""t really been there when the picture was taken, but were a post accident embellishment.
A digital camera with apparatus for authentication of images produced from an image file is disclosed in U.S. Pat. No. 5,499,294. Referring to FIG. 3A of U.S. Pat. No. 5,499,294, a block diagram of a system including a digital camera is shown that produces a file image with a digital signature. A device specific decryption key is required to allow a file image to be authenticated. Furthermore, in order to determine whether a file image is authentic, the person performing the authentication must know which camera took the picture; due to the fact that each camera includes a unique private encryption key.
SUMMARY OF THE INVENTION
It is desirable to provide an improved method and system for determining the authenticity of a sample of an environment. A digital signature is created that is a function of both the sample of the environment itself, as well as at least one parameter that is representative of at least one condition under which the digital sample was acquired. The sample is stored in memory together with the at least one parameter and the digital signature. Authenticity of the stored image is determined by creating a new signature from the stored image and at least one parameter, and then comparing the two signatures to determine if they are the same.
Such a method and apparatus is advantageous for several reasons. First, one aspect of the present invention is that it is not necessary to know what device sampled the environment because it only is necessary to have the stored sample, parameters, and signature. Second, encryption is not required for authentication purposes, thereby allowing information storage devices to be manufactured in a more cost effective manner.
Other features and advantages of the present invention will become apparent from the following description.